MEM switches in various forms are well-known in the art. U.S. Pat. No. 5,121,089 to Larson, granted in 1992, describes an example of a MEM switch in which the armature rotates symmetrically about a post. Larson also suggested cantilevered beam MEM switches, in “Microactuators for GaAs—based microwave integrated circuits” by L. E. Larson et al., Journal of the Optical Society of America B, 10, 404–407 (1993).
MEM switches are very useful for controlling very high frequency lines, such as antenna feed lines and switches operating above 1 GHz, due to their relatively low insertion loss and high isolation value at these frequencies. Therefore, they are particularly useful for controlling high frequency antennas, as is taught by U.S. Pat. No. 5,541,614 to Lam et al. (1996). Such use generally requires an array of MEM switches, and an N×N array of MEM switches requires N2+1 output lines and N2 control circuits for direct electrical control. These control lines may need to be shielded to avoid interfering with the high frequency antenna lines, and accordingly add considerable complexity and cost to the fabrication of these switches.
MEM capacitors are also very useful for controlling very high frequency phased array antennas and the like. Due to the fact that electrical control lines associated with MEMS capacitors can interfere with the operation of a phased array, shielding those control lines would add considerable complexity and cost to the fabrication of phased array antennas.
Thus, there exists a need for controlling the MEM devices, both switches and capacitors, in such an array by a means which reduces the difficulties imposed by routing control lines.